An indepth look at weather and climate by South Carolina's Weatherman Jim Gandy.

Saturday, January 28, 2012

Decline in Solar Output Unlikely to Offset Global Warming

This is a repost of a press release from the UK Met Office issued on January 23, 2012.

Image Credit: NASA/SDO.

New research has found that solar output is
likely to reduce over the next 90 years but that will not substantially
delay expected increases in global temperatures caused by greenhouse
gases.

Carried out by the Met Office and the University of
Reading, the study establishes the most likely changes in the Sun's
activity and looks at how this could affect near-surface temperatures on
Earth.

It found that the most likely outcome was that the Sun's
output would decrease up to 2100, but this would only cause a reduction
in global temperatures of 0.08 °C. This compares to an expected warming
of about 2.5 °C over the same period due to greenhouse gases (according
to the IPCC's B2 scenario for greenhouse gas emissions that does not
involve efforts to mitigate emissions).

Gareth Jones, a climate
change detection scientist with the Met Office, said: "This research
shows that the most likely change in the Sun's output will not have a
big impact on global temperatures or do much to slow the warming we
expect from greenhouse gases.

"It's important to note this study
is based on a single climate model, rather than multiple models which
would capture more of the uncertainties in the climate system."

The
study also showed that if solar output reduced below that seen in the
Maunder Minimum - a period between 1645 and 1715 when solar activity was
at its lowest observed level - the global temperature reduction would
be 0.13C.

Peter Stott, who also worked on the research for the Met
Office, said: "Our findings suggest that a reduction of solar activity
to levels not seen in hundreds of years would be insufficient to offset
the dominant influence of greenhouse gases on global temperatures in the
21st Century."

During the 20th Century
solar activity increased to a 'grand maximum' and recent studies have
suggested this level of activity is at or nearing its end.

Mike
Lockwood, an expert in solar studies at the University of Reading, used
this as a starting point for looking at the most probable changes in the
Sun's activity over the 21st Century.

Met Office scientists then placed the projections into one climate model to see how they may impact temperatures.

Professor
Lockwood said: "The 11-year solar cycle of waxing and waning sunspot
numbers is perhaps the best known way the Sun changes, but longer term
changes in its brightness are more important for possible influences on
climate.

"The most likely scenario is that we'll see an overall reduction of the Sun's activity compared to the 20th
Century, such that solar outputs drop to the values of the Dalton
Minimum (around 1820). The probability of activity dropping as low as
the Maunder Minimum - or indeed returning to the high activity of the 20th
Century - is about 8%. The findings rely on the assumption that the
Sun's past behaviour is a reasonable guide for future solar activity
changes."

About Me

A professional meteorologist for over 37 years, Jim Gandy is the chief meteorologist at WLTX-TV (CBS affiliate) in Columbia, SC. He has held that position since 1999.
Jim is a Certified Broadcast Meteorologist and has a number of awards and recognitions for his work over the years. He is best known for his forecast of Hurricane Hugo in 1989 and his work during the tornado outbreak in South Carolina in 1994.
Jim continues to study weather and is interested in climate change which he has studied since 2005. Looking for better ways to communicate climate change, he is working with the Center for Climate Change Communication at George Mason University and with Climate Central.
Jim recently began working with the Helmuth Lab at the University of South Carolina. Dr. Brian Helmuth is working in the area of the effects of climate change on the ecology.
All of these subjects are of vital interest to South Carolina.